The invention relates to an improved rubber pneumatic tire for vehicles which has two beads which lie on the rim of a wheel and in each of which is embedded a core ring around which is laid a carcass insert which is embedded into the rubber, for anchoring the insert. The invention also relates to a process for the production of such pneumatic tires.
It is known for the core rings which are arranged in the beads of pneumatic tires to be made from metal such as steel, for example in the form of shaped metal sheet or wires which are wound in a portionwise manner.
As metals such as steel do not have any particular affinity for the rubber of pneumatic tires, problems are involved in joining the known core rings to the tire material. The elastic bent individual wires have a tendency to spring back, as a result of the bending stress. Upon vulcanisation, that is to say when the rubber is briefly fluid, in the worst cases the above-indicated phenomenon results in structural disorder in the core rings. Added to that is the fact that, by virtue of the specific gravity of the core ring being markedly different from the rest of the tire material and also by virtue of the specific form of the core ring, the core ring represents a source of imbalance phenomena, the disadvantageous effect of which increases in proportion to a lighter tire construction and in proportion to an increasing speed of travel that the tire is designed to withstand.
As the conventional core rings are enclosed by the incoming ends of the carcass insert, that structure gives stiffened bead regions which extend to a substantial distance into the side walls of the tire, so that the comfort properties of the tire suffer as a result.